Preheat your oven to 350°F and grease a 9x5 inch loaf pan (or 8x8 inch square pan) with butter or oil, making sure to coat the bottom and all sides evenly. This prevents sticking and ensures even browning on the edges.

In a large bowl, mash the banana until completely smooth—this ensures even moisture distribution throughout the bread. Add the eggs, mashed banana, maple syrup, and vanilla to the bowl, whisking vigorously until well combined and the mixture is lighter in color and slightly frothy, about 1-2 minutes. This aerates the batter and helps create a tender crumb. Fold in the finely shredded zucchini that you've squeezed dry with a towel—removing excess moisture is crucial to prevent a soggy loaf.

In a separate bowl, whisk together the almond flour, coconut flour, cinnamon, baking soda, salt, and nutmeg until evenly combined with no lumps. I like to sift the flours together first—this breaks up any clumps and helps distribute the leavening agent and spices more evenly, which gives you a more consistent texture throughout the bread.

Pour the dry ingredient mixture from Step 3 into the wet ingredients from Step 2, folding gently with a spatula until just combined. Do not overmix—gluten-free batters benefit from minimal stirring, as overworking can make the bread dense. Stop as soon as you no longer see streaks of dry flour.

Pour the batter into your prepared pan from Step 1, smoothing the top gently with a spatula. Bake in the preheated 350°F oven for 55-60 minutes, until a toothpick inserted in the center comes out clean or with just a few moist crumbs. The top should be golden brown and a cake tester should meet slight resistance.

Remove the bread from the oven and let it cool in the pan for 15-20 minutes before turning it out onto a wire rack to cool completely. This resting period allows the crumb structure to set so the bread won't fall apart when you remove it from the pan. Slice and serve at room temperature or slightly warm.